1. Technical Field
This invention relates generally to the gasification of liquid fuels and, more particularly, to the gasification of petroleum, alcohol, and other combustible liquids for mixture with atmospheric air for combustion in internal combustion engines.
Most fuel injected into a combustion chamber of an internal combustion engine does not burn in the combustion chamber. For example, only about 29-30% of gasoline undergoes combustion in conventional fuel injected automobile engines. Most of the unburned fuel passes through the exhaust manifold and is burned in a catalytic converter. Standard fuel injection systems do not vaporize fuel, but atomize the fuel into small enough droplets so as to allow some of the liquid droplets to burn upon ignition. Although atomization increases the surface area exposed to a spark or other burning gases, the fuel is still in a liquid form. A volatile fuel such as gasoline, for instance, is much more explosive when in a purely gaseous form since the combustion rate of a gas is much greater than that of a liquid. Much of the atomized fuel must absorb energy to overcome the latent heat of vaporization to become a gas. Thus, during the ignition process, a portion of the liquid gasoline actually burns at lower combustion rate than vaporized gasoline. Furthermore, much of the atomized gasoline simply absorbs the heat of combustion during ignition, vaporizes, passes through the exhaust manifold of the engine where it is finally burnt in the catalytic converter where temperatures reach in access of 5000.degree. fahrenheit. Partial combustion of fuel results in low engine power performance and low fuel efficiency.
Another unfortunate result of incomplete combustion is the production of carbon monoxide. Thus, in addition to unburnt volatile fuel which escapes through the exhaust system, carbon monoxide is produced. The presence of these unwanted byproducts of incomplete combustion requires the addition of a catalytic converter to the exhaust system of the engine, sometimes including additional gas tubes which recycle unburnt gases from the catalytic converter back to the intake manifold of the engine. The addition of such equipment increases the cost and complexity of the engine system.
Accordingly, there is a need for a fuel system which facilitates complete gasification of liquid petroleum or other volatile fuel products so that a high percentage of combustion may occur immediately upon ignition, thereby increasing engine power output, fuel efficiency, and eliminating the need for equipment which reduces harmful emissions resulting from incomplete combustion.
2. Description of the Prior Art
Others have recognized the need to increase the efficiency of internal combustion engines while decreasing the amount of harmful gases produced as a result of incomplete combustion. Many approaches may be taken to increase combustion efficiency. For instance, U.S. Pat. No. 4,149,853 increases the percentage of fuel combustion by introducing organic reactive intermediates to an air-fuel mixture prior to ignition. There, reactive intermediates are generated from a suitable source compound, such as acetone. The acetone is exposed to ultraviolet light, converted to a short lived free radical, and combined with a heavier hydrocarbon molecule to create a longer-lived radical. The radicals are then introduced to the fuel before the ignition point, resulting in a very high percentage of burning of the fuel.
Others have attempted to increase the percentage of fuel combustion by highly atomizing the fuel just prior to ignition. For instance, U.S. Pat. No. 2,351,072 discloses a method of producing vaporous mixtures of air and a liquid in a finely divided state.
U.S. Pat. No. 4,426,984, discloses a generator for converting volatile combustible liquids, such as gasoline or methanol into an aeriform gas. The generator consists of a closed vessel containing liquid gasoline maintained at a predetermined level. The liquid gasoline is evaporated by allowing desiccated air to pass directly through the liquid. The air-gasoline mixture is then passed through a charcoal material which stabilizes the gas into an aeriform, which is fed into an internal combustion engine.
While others have attempted to increase the combustion efficiency of internal combustion engines, no such design has been developed which would increase the combustion efficiency to over 90% while reducing the fuel feed system complexity. By achieving those goals, power output and fuel efficiency are increased while harmful emissions and overall operating cost of the engine are decreased.